What effect does nuclear radiation have on atoms?
Nuclear radiation (i.e. the radiation produced by unstable nuclei) can unstabilize the atom, depending on its properties.
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium.
The majority of radiations emitted by nuclei are ionizing: they are a high-energy density radiation, e.g. plutonium. It means that they can create a chain reaction on materials. Maybe the best example are living tissues, that has their structures degradated by radiation.
Thus, the effect of nuclear radiation on atoms is either unstabilizing the nucleon or their electron cloud, for example in elements used on lamps, fluorescent lamps.
"Nuclear transmutation is the conversion of one chemical element or an isotope into another. A transmutation can be achieved either by nuclear reactions (in which an outside particle reacts with a nucleus) or by radioactive decay (where no outside particle is needed)."